What shape is formed with a base and a pointed top, representing a three-dimensional form?

A pyramid is defined by its unique structure, which includes a polygonal base and triangular faces that converge at a single apex or pointed top. This characteristic makes it a three-dimensional geometric figure.

In contrast, a circle is a two-dimensional shape with all points equidistant from the center, lacking a pointed top or base. A rectangle, also a two-dimensional shape, consists of four right angles and does not have a pointed top or any three-dimensional aspect. Lastly, a triangle is a two-dimensional figure formed by three sides and three angles, but it does not possess the height or apex that characterize a pyramid.

Therefore, the distinguishing feature of a pyramid is its combination of a base and pointed top, enabling it to be recognized as a three-dimensional form.